The present invention relates to a control apparatus for operational control of passenger restraining safety devices such as side air bags.
A conventional control apparatus for operating a side air bag of a passenger restraining safety device for a vehicle in order to protect a passenger against a lateral collision of the vehicle comprises satellite collision detecting circuits including collision sensors, e.g., acceleration sensors, mounted on parts, or at positions that will confront and most accurately detect a lateral collision, and a controller mounted on a part, or at a position most likely to be unaffected by a collision of the vehicle, such as a center floor tunnel of an automobile. The satellite collision detecting circuits and the controller are interconnected by communication lines so that a satellite collision detecting circuit which has detected a collision exceeding a predetermined magnitude causes the side air bag at the corresponding side to operate.
For such conventional control apparatus for a passenger restraining safety device, those parts, or positions, on or at which the satellite collision detecting circuits are mounted, are selected so that the impact of a collision will be detected with good accuracy, and the collision sensors will be subjected to the greatest force and damage upon occurrence of a lateral collision. In addition, the layout of the communication lines needed for interconnecting the satellite collision detecting circuits and the controller must be carefully designed so that a collision will not cause disconnection of the communication lines. Validation that there is no disconnection of the communication lines from a collision is established via testing, i.e., repeatedly running vehicle collisions and inspecting the crushed vehicle bodies to determine if there is disconnection of the communication lines.
Therefore, development of such conventional control apparatus for passenger restraining safety devices requires large-scaled experiment facilities as well as a great amount of time and labor for testing in order to provide the required verification that there is no disconnection of the communication lines as a result of the collision. These factors are the principal reasons as to the high cost of such conventional control apparatus for passenger restraining safety devices. Furthermore, because of design rules imposed on the layout of communication lines, there is little flexibility in the layout design, which also increases cost.
To address such problems of the conventional control apparatus for passenger restraining safety devices, the present invention provides a control apparatus for passenger restraining safety devices which effects secure operation of the passenger restraining safety device to keep a passenger safe even if there is a disconnection of a communication line as a result of a collision.
The control apparatus for passenger restraining safety devices includes a collision detection circuit disposed on a part, or at a position that will confront and accurately detect a lateral collision of a vehicle, a restraining device controller disposed on another part, or at another position of the vehicle, and a passenger restraining device operatively controlled by the restraining device controller. The collision detection circuit and the restraining device controller are interconnected by a communication line, wherein the collision detection circuit outputs a normal condition signal with a predetermined period when no collision is detected, an arithmetic operation start signal with a predetermined period when a collision is first detected, and a restraining start signal with a predetermined period when the detected collision exceeds a predetermined magnitude. The restraining device controller provides an operation command to the passenger restraining device when the restraining start signal is received and also when a defective communication develops after reception of the arithmetic operation start signal.
In the control device for passenger restraining safety devices, while a vehicle is traveling normally, the collision detection circuit repeatedly sends the normal condition signal, having a predetermined high rate period, via the communication line to the restraining device controller. When a lateral collision occurs which exceeds a minimum magnitude, the collision detection circuit sends the arithmetic operation start signal via the communication line to the restraining device controller, and when an integral value corresponding to the magnitude of the collision becomes equal to, or larger than a predetermined magnitude, greater than the minimum magnitude, sends the restraining start signal via the communication line to the restraining device controller, and the restraining device controller directs the passenger restraining device to operate to protect a passenger.
Where a collision has occurred, the arithmetic operation start signal is sent from the collision detection circuit via the communication line to the restraining device controller before significant damage to the vehicle occurs. Subsequently, if the vehicle is so seriously damaged from the collision that a disconnection of the communication line results, since the restraining device controller has received the arithmetic operation start signal and has failed to receive a subsequent signal, or receives a defective signal, the restraining device controller operates under condition that a collision has occurred and directs the passenger restraining device to operate to protect a passenger.